Traditionally, a spinner covering a hub is provided to create an aerodynamic surface around the hub and the blade roots, and to protect the hub, the blade root, and the flanges from the weather.
During the lifetime of a wind turbine, service operations have to be undertaken at regular time intervals. Many of the service operations requires service personnel to access the hub, which often on modern wind turbines is a hollow cast iron structure. Some service actions may require access between the hub and the spinner. Such access can be difficult and uncomfortable to the personnel, who may have to climb or crawl in narrow spaces when performing different actions.